While Brooklyn Nine-Nine eventually changed Rosa into a private investigator, this twist caused a plot hole—or, arguably, it could be a secret moment of genius for the sitcom. Brooklyn Nine-Nine’s final season made a concerted effort to address problems with policing. The majority of the sitcom’s seven preceding seasons largely ignored real-life issues with the police (outside of a few standalone outings such as Brooklyn Nine-Nine season 4, episode 16, “Moo Moo”). However, changing attitudes toward the police in 2020 (particularly in the aftermath of George Floyd’s murder) led the creators of Brooklyn Nine-Nine to change this approach in season 8.
https://screenrant.com/brooklyn-99-rosa-quit-nypd-plot-hole/